These windows are based on the traditional Gothic cathedral window but instead of using glass Polke has incorporated thin slices of Agate.
What I love about Polke's windows is the colouring.....the teals, greens, pinks, blues....fabulous.
Pictured below is one of the windows while still on the bench in process. Some of the other agate windows are in the background finished but in the studio, pre-installation.
All the images were obtained from Google images so I'm not able to assign credit to the correct photographers.